【正文】
lly intensive and may be iterative. 這個(gè)過程在數(shù)值上是密集且可重復(fù)的。 The decoder for VQ takes an image vector and pares it to stored vectors in the codebook. VQ的譯碼用一個(gè)圖像矢量與碼本中存儲(chǔ)的矢量比較。 A selection is made based on minimization of a distortion function between the new vector and the codebook. 在新矢量和碼本之間可根據(jù)失真函數(shù)的最小值進(jìn)行選擇。 The VQ technique can generally achieve pression ratios of between 20 to one and 35 to one with little observable distortion. VQ技術(shù)通常能在很難觀察到失真的情況下達(dá)到 30: 1和35: 1的壓縮比 The VQ technique is an example of asymmetric pression in that considerably more time is spent deriving the codebook than in depression via a codebook lookup. VQ技術(shù)是將大量時(shí)間用于推導(dǎo)碼本而不是通過碼本的查找來進(jìn)行解壓縮的不對(duì)稱壓縮的一個(gè)實(shí)例。 Since different images may have different characteristics, a robust codebook is necessary to successfully code and decode Landsat and other satellite images. 對(duì)于不同的圖像有著不同的特征。要成功地對(duì)地球資源衛(wèi)星和其他衛(wèi)星圖像進(jìn)行編碼和解碼,就必須有一個(gè)穩(wěn)定的碼本。 A VQ technique using between channel correlation as well as spatial correlation achieves higher pression rates with less loss than independent band VQ. 用于信道相關(guān)以及空間相關(guān)之間的 VQ技術(shù)在較小損失的情況下,產(chǎn)生更高的壓縮比。 The last type of pression considered is fractal pression. 要考慮的最后一類壓縮方法就是分形壓縮。 Based on Mandelbrot sets which take advantage of a self similar, scaling independent, statistical feature of nature, fractal pression and depression involves a clustering approach to finding regions which exhibit the same characteristics as a sample region without regard to rotation and scale. 它以曼德羅集為基礎(chǔ),具有自相似、獨(dú)立尺度變換、自然統(tǒng)計(jì)特性的特點(diǎn)。分形壓縮和解壓縮涉及到用集群法在不考慮旋轉(zhuǎn)和尺度變換的情況下,尋找一個(gè)展示相同特征作為樣本區(qū)域的區(qū)域。 Regions within an image are related to numerous other regions within the same image, with this duplication of information being the basis of the pression potential. 圖像中的某些區(qū)域與同一圖像中許多其他區(qū)域是相關(guān)的,并以此信息的重復(fù)性作為提高壓縮潛力的基礎(chǔ)。 Fractal pression can achieve pression ratios of up to 80 to one with only moderate loss of information, the fractal technique, like the VQ technique is also asymmetric. 分形技術(shù)可在很少的信息損失時(shí),產(chǎn)生高達(dá) 80: 1的壓縮比。分形技術(shù) VQ一樣也是不對(duì)稱的。 Hardware implementation of the depression fractal images has achieved real time rate. 分形圖像的硬件解壓縮已達(dá)到了實(shí)時(shí)水平。